There is a growing need in the textile market for siloxane fabric softeners that not only provide softening but also impart hydrophilicity and other desirable properties to the treated fabric. Using a conventional siloxane polymer as the active ingredient in a fabric treatment agent often requires a trade-off in properties.
Amine-functional polysiloxanes are known to improve the hand of textiles. `Hand` means the softness and smoothness of the textile. The hand of a treated textile is directly related to the amine content (e.g., the number of amino-functional groups) of the polysiloxane. Generally, as the amine content increases, the hand of the textile improves.
One method to produce amine-functional siloxane compounds for use as fabric treatment agents is to react an epoxy-functional silicone with an amine-functional organic compound. This method is described in U.S. Pat. No. 4,409,267 to Ichinohe et al., Oct. 11, 1983, which discloses a fabric treatment composition. The organopolysiloxane is prepared by a process comprising: 1) reacting a silanol-functional organopolysiloxane with a polyoxyalkylene compound and an epoxy-functional compound, by addition reaction and thereafter 2) reacting an amine compound with the epoxy group of the epoxy-functional organopolysiloxane, by addition or condensation reaction. The reactions are typically carried out in the presence of a solvent. The solvent and any impurities formed during reaction must then be removed. This method suffers from the drawback that unsubstituted amine groups can be present, which cause yellowing when the organopolysiloxane is applied to fabrics.
U.S. Pat. No. 5,593,611 to Czech, Jan. 14, 1997, discloses a fabric treatment composition comprising an aminopolysiloxane. The aminopolysiloxane is prepared by hydrolyzing and condensing an amino-functional dialkoxysilane with water in the presence of heat and a base catalyst. The aminopolysiloxane is hydrophobic and has a molecular weight of at least 30,000.
U.S. Pat. No. 4,757,121 to Tanaka et al., Jul. 12, 1988, discloses a fiber softening composition for synthetic fibers. The composition contains a combination of 2 different amino-substituted organopolysiloxanes, an epoxy-substituted alkoxysilane, and a monoepoxy compound. The first amino-substituted organopolysiloxane is terminated with a hydroxy group or alkoxy group that reacts with the epoxy-containing alkoxysilane. This forms a film of a crosslinked composition on the fiber surface. The second amino-substituted alkoxysilane is trialkyl-silyl terminated, and the second organopolysiloxane is prepared by reacting an amino-containing organopolysiloxane with a liquid organic epoxy compound.
U.S. Pat. No. 4,680,366 to Tanaka et al., Jul. 14, 1987, discloses a fabric finishing agent containing an organopolysiloxane with primary and secondary amine-functional hydrocarbon groups and polyoxyalkylene groups. The organopolysiloxane can be emulsified in water and applied to fabric to provide softness and anti-static properties. The organopolysiloxane is prepared by reacting a polyoxyalkylene glycidyl ether with an amino-functional organopolysiloxane.
However, the amine-functional polyorganosiloxanes suffer from the drawback that as the amine content of the polyorganosiloxane increases, the tendency of the textile to discolor or yellow increases. Additionally, the amine-functionality tends to impart hydrophobicity to the treated textile.
To minimize yellowing, it has been the practice in the textile industry to impart softness to a textile by applying a modified polysiloxane, which contains amide groups or carbamate groups instead of amine groups. However, amide and carbamate groups do not provide the same desirable level of softness characteristic of the amine groups.
For example, another method for producing amine-functional siloxanes for use in fabric treatment agents is disclosed in "Structure Activity Relationships of Aminofunctional Siloxanes as Components in Softening Finishes", Textile Chemist and Colorist, by Lautenschlager et al., published March 1995, Vol. 27, No. 3. Lautenschlager et al. disclose that epoxidation is not a viable alternative to an improved softener because of impurities formed during the reaction. Alternatively, Lautenschlager et al. disclose acylated aminofunctional silicones that can be used in fabric softening finishes, and a method for their preparation by acylation of an aminofunctional silicone fluid. The acylating agent can be an anhydride, lactone, or carbonate. However, the resulting acylated aminofunctional silicones exhibit a decline in hand when compared to standard aminosiloxanes.
Therefore, it is an object of this invention to provide a blend of siloxanes having amine- and polyol-functional groups that can be used in fiber treatment compositions.
U.S. Pat. No. 5,277,968 to Canivenc, Jan. 11, 1994, discloses a process for treating a textile fabric. The process comprises applying an aqueous emulsion of a polydiorganosiloxane to the fabric. The polydiorganosiloxane has secondary and tertiary amine-groups and hydroxyl-groups.
U.S. Pat. No. 5,118,535 to Cray et al., Jun. 2, 1992, discloses a method for treating fibrous materials comprising applying a composition containing a cyclic diamine functional polydiorganosiloxane. The composition can be a solution, dispersion, or emulsion.
EP A2 0 399 706 by Cray, published on Nov. 28, 1990, discloses a method for treating fibrous materials. The method comprises pre-reacting an amine-containing organosiloxane with a monoepoxide, and thereafter applying the resulting product to the fibers. The product has primary, secondary, and tertiary amine groups, where up to 10% of the amine groups are primary amine groups.
U.S. Pat. No. 4,311,626 to Ona et al., Jan. 19, 1982, discloses a composition containing an aminofunctional polydiorganosiloxane and a carboxylfunctional polydiorganosiloxane. The composition is used to treat fibers to impart smoothness, crease resistance, elongation recovery, and compression recovery. However, carboxyl groups detrimentally affect the hand of the treated fibers.
U.S. Pat. No. 4,366,001 to Ona et al., Dec. 28, 1982, discloses a fiber treating composition that contains at least 2 or 3 types of organofunctional siloxanes. The first is an amino-functional siloxane, the second is a carboxyl-functional siloxane, and the third is an epoxy-functional siloxane. At least one of the organofunctional siloxanes contains at least one polyoxyalkylene group. The composition provides antistatic character, moisture absorbability, stain resistance, pliability, smoothness and compression recovery.
However, none of these references disclose a fiber treatment composition that imparts hydrophilicity and provides resistance to yellowing to textile fibers, without a detriment to hand. Therefore, it is a further object of this invention to provide a fiber treatment composition that provides all of these desired properties.